TL;DR
This vacuum (Dyson Outsize) failed after just 2.5 years of light use, and extensive troubleshooting made it clear that the only remaining fix is an expensive core replacement, which feels unacceptable for the price point.
Product usage and failure:
This vacuum was purchased about 2.5 years ago and used in a small household with one person and one pet, so the usage has been light to normal for a cordless machine. It performed very well until roughly three weeks ago, when it suddenly shut down mid‑clean with the LCD going black, then would only power on for ~3 seconds before cutting out again, even on a full charge.
Troubleshooting steps taken (part 1):
Before reaching out for support, every reasonable step was taken to rule out simple issues.
• Swapped in a second, fully charged battery and confirmed the charger lights indicated both batteries were healthy.
• Power‑cycled the vacuum by removing the battery for a few minutes, then retesting in case of a minor software or control‑board glitch.
• Completely emptied and cleared the bin, inlet, wand, neck, and cleaner head so that all air passages and cyclones were visibly unobstructed.
• Washed and fully dried the pre‑filter according to the manual before reinstalling and testing again.
Troubleshooting steps taken (part 2) Manufacturer support response:
Support was contacted with the serial number and a clear description of the issue: fully charged battery, black screen, and the machine shutting down after ~3 seconds of runtime. After working through their scripted troubleshooting, nothing improved, and the only explanation given was that the unit was outside the standard 2‑year cordless warranty, so no repair or goodwill replacement would be offered. The only option presented was purchasing a new main body/cyclone assembly at roughly the cost of $350, which essentially means buying the heart of the machine again just 2.5 years after the original purchase.
Troubleshooting steps taken (part 3):
In an effort to avoid throwing away such an expensive product, the vacuum was completely disassembled down to individual components using precision screwdrivers, a process that took several hours and multiple trips for tools. Every part was thoroughly cleaned, left to dry overnight, and then reassembled, yet the exact same behavior persisted the next day: black screen and shutdown after ~3 seconds of operation.
Overall assessment
At this point, the most likely culprit appears to be a failed control board/PCB or related internal electronics, which are not realistically user‑serviceable. For a premium vacuum at this price point, a major, non‑repairable failure after only 2.5 years of light use, and a support experience that offers only an expensive core‑part purchase, feels extremely disappointing and erodes confidence in the brand.